Synchronization Algorithm Based On OFDM Wireless Communication System

OFDM is the key technique of the physical layer for the fourth generation mobile communication. The advantage of OFDM is to resist of the multipath channel.OFDM improves the utilization efficiency of the spectrum. It enhances the capacity of the system and meets the request of the high speed of data transmission and user's movement for the next generation mobile communication.OFDM is more sensitive in the frequency offset and the phase noise than the single carrier communication system, since the frequency offset will break the orthogonality of the sub-carriers, introduce the interference of the sub-carriers, and bring very great influence to the system performance. Synchronization is one of the key techniques of the OFDM.This paper chiefly studies the synchronization of OFDM, and includes the algorithm and actualization.This paper studies the carrier synchronization and the symbol timing synchronization. Thinking of the characteristic of data transmission over the wireless channel, the synchronization achieves at the period of the preamble of the frame in the receivers. We chiefly discuss the algorithm based on the training sequence.The end of paper presents a scheme of OFDM system based on the software defined radio. The scheme refers to the preamble of IEEE802.11a, and utilizes the framework of the "DSP+FPGA+ASIC" to transmit at the intermediate frequency. Firstly, this paper introduces the main parameter, preamble and the hardware organization. Then it proposes an improved algorithm of the frame detection, and makes simulations and analysis. Comparing with the algorithm in existence, the algorithm resolves the difficulty of timing in the correlation flat based on the preamble of IEEE802.11a.It costs less calculation and implements easily on hardware platform. The algorithm can perform in the case of low SNR. Finally, analysis of the algorithm and the design of the multipath channel model are presented.